Resonator and resonance device

A resonator comprising:

• a base;
• a first vibration arm extending from the base in a first direction, the first vibration arm having a first width;
• and
• a second vibration arm extending from the base in the first direction with a first gap between the first and second vibration arms;
• a third vibration arm extending from the base in the first direction adjacent to the second vibration arm;
• and
• a fourth vibration arm extending from the base in the first direction with a gap between the fourth vibration arm and the third vibration arm,
• wherein the first and second vibration arms are configured to perform out-of-plane bending vibration with opposite phases at a predetermined frequency when a potential is applied thereto,
• wherein the first and second vibration arms are configured to perform the out-of-plane bending vibration in a thickness direction of the resonator, and
• wherein a ratio of a width of the first gap to the first width of the first vibration arm is within a range that configures the resonator to have an absolute value of rates of variations in the predetermined frequency with respect to variations in the first width and in the width of the first gap to be approximately 100 ppm or less.